APUG isn't going to like this answer, but I would suggest sending them off to scancafe. For a small (<1000) batch of negs, it will be affordable (certainly compared to buying a good enough scanner) and you will get professional results. Make sure you take the option to get the raw 16-bit scans so you can make adjsutments yourself when necessary, and you can consider the copies archival. They're probably not even C-41 negs and they are likely to have faded past the point where they can be corrected in an optical printing process.

By all means if you're setup for RA-4 and competent with it, give them a go. However, learning colour printing on some precious yet delicate, old and faded negatives from the wrong process sounds like hell to me.